A chain formed of interconnected flat links

ABSTRACT

A chain composed of interconnected links, each link having sides with inner longitudinal edges and a cylindrical hook end and a pintle stub at opposite ends and in which the cylindrical hook and stub have outer edges spacedly inward of the inner edges of the sides and the outer edges are joined by a semicircular juncture, and the chain formed of flat metal strip stock by stamping elongated parallel notches in the stock parallel to and inwardly of the edges, and scoring transversely across the center section between the notches; severing along the score and bending one part of the center section to form a pintle end of a link and bending the other part of the center section arcuately to form a hook end of the link that journals on the pintle end of an adjacent link.

United States Patent Inventor Joseph T. Chester Fulton, ll].

Mar. 1 1, 1968 Apr. 13, 197 1 Richard A. Kummerer Fulton,

Alfred Den Beston Fulton, Ill. a fractional part interest to each Appl. No. Filed Patented Assignees A CHAIN FORMED OF INTERCONNECTED FLAT LINKS 483,843 10/1892 Hart 74/248 1,107,808 8/1914 Locke 74/248 3,262,547 7/1966 McAuley 1. 74/249 3,215,256 11/1965 McAuley 74/249X v FOREIGN PATENTS 351,879 7/1931 Great Britain 74/249 Primary Examiner-Leonard l-I. Gerin Att0rneyWilliam A. Murray ABS i' CT: A chain composed of interconnected links, each link having sides with inner longitudinal edges and a cylindrical hook end and a pintle stub at opposite ends and in which the cylindrical hook and stub have outer edges spacedly inward of the inner edges of the sides and the outer edges are joined by a semicircular juncture, and the chain formed of flat metal strip stock by stamping elongated parallel notches in the stock parallel to and inwardly of the edges, and scoring transversely across the center section between the notches; severing along the score and bending one part of the center section to form a pintle end of a link and bending the other part of the center section arcuately to form a hook end of the link that journals on the pintle end of an adjacent link.

Patentw April 13, 191

INVENTOR. JOSEPH T. CHESTER ATTORNEY l A CTIAHN FORMED T ENTERCONNECTIED FLAT LHNK BACKGROUND OF THE INVENTION This invention relates to a chain link and to the method of forming a chain link. More particularly the invention relates to a chain link that has a hook end narrower than the spacing between the sides of the links so that misalignment of sprockets in the drive will not cause excessive wear between the adjoining links. Still more particularly the invention relates to links that are formed from a continuous strip of stock, each link of which has as one of its first steps in being formed the stamping of a pair of parallel elongated slots with rounded ends so that the pintle portion and hook portion formed from the stock between the slots have smooth junctures with the sides and ends of the respective links.

It has heretofore been known to form links and chains from a continuous strip of flat steel stock by providing elongated side scores inwardly of the edges and across the material. The material is then severed by dies by ripping of tearing the material along the scores to form pintle and hook portions. Such a method of and apparatus for producing such chain links are shown in US. Pat. 1,786,707.

A problem that exists in chains produced by such a method is that there are high potential failure points created at the terminations of the rips along the scores. This condition often results in early failure of the chain and, of course, a shutdown of the machine or device being moved by the chain.

Also, since each individual link is constructed in exactly the same manner, the transverse width of the pintles and hooks are substantially equal to the transverse width of the openings in the chains. Due to the nature of. ripping that creates the pintles and hooks, there are created large burrs and uneven edges on the hooks, pintles and sides. This creates wear points and uneven distribution of load between the links. Further, should the sprockets be misaligned, the pintles and hooks of adjacent links will not seat properly on one another since there is no sidewise tolerance between the pintles, hooks and chain link sides.

SUMMARY With the above in mind it is the primary object of the invention to provide chain links formed from a continuous strip of flat stock by a method having a first step of stamping a pair of parallel elongated slots that are rounded at their ends. The pintles and hooks are formed by bending the material between the slots. Therefore the junctures between the hooks and pintles and the sides of the link are the rounded ends of the slots. This creates smooth junctures and consequently eliminates the tenninal rips or tears that exist in links produced by the previous method. Also, since the pintles and hooks are narrower that the respective chain openings, misalignment between the sprockets can be partially, if not completely, compensated for by sidewise shifting between the links.

BRIEF DESCRIPTlON OF THE DRAWINGS FIG. 1 is a plan view of a portion of a metal strip of stock as it is being formed into a chain.

FIG. 2 is a sectional view taken along the line 2-2 of the structure shown in FIG. ll.

FIG. 3 is an underside view of a single link.

FIG. 4 is a side view of a single link.

I DESCRIPTION OF THE PREFERRED FORM Referring now to FIGS. l and 2, the chain links are fonned from a continuous strip of metal stock that is fed through a suitable die device. The first step in fonning the chain link, as shown in the extreme left ends of FIGS. l and 2, is the step of punching a pair of parallel elongated slots lil, l2 in the stock. The slots are spaced inwardly from the longitudinal edges of the stock and have opposite rounded ends 13, I4 and 115, T6

respectively. At substantially the same time a transverse score 17 is formed in the underside of the center section 18 between the slots 11, 12.

As the strip it) moves along the die to the step shown at A, the center section 18 is severed along the score 17 to divide the section 18 into a short tab portion 19 adjacent the ends 13, 15 and a long tab portion 20. The tab portion 19 is bent upwardly and the tab portion 20 is bent downwardly with its end bent upwardly.

As the strap 10 is moved further along the die to a step shown substantially at B, the long tab portion 20 is continued to be bent upwardly while at the same time a score 21 is formed in the underside of the strip between slot ends 14, 16 of one length of chain and slot ends 13, 15 of the adjacent length of chain. At the same time transverse arcuate portions 22, 23 are formed on opposite sides of the score 21.

The next step, shown at C, is to sever the link along the score line 21 and to bend the tab portion 19 to create with the arcuate end portion 23 of the substantially completed link a semicylindrical pintle end of the link. Also, the long tab portion 20 is continued to be bent vertically. At D, the chain link is completed by continuing to bend the long tab portion 20 into a hook or cylindrical portion that encircles the pintle end of the next adjacent link.

Thus, and referring now to FIGS. 3 and 4, each link 30 is formed in the above manner is composed of a pair of flat longitudinal sides 31, 32 having parallel outer edges 33, 34 and inner edges 35, 36 respectively. The edges 35, 36 are the outer edges of the slots 11, 12. The sides 31, 32 are interconnected at their ends by the arcuate end portions 22., 23 that extend between the edges 33, 34. Laterally inwardly of the edges 35, 36 are the longitudinal edges 37, 38 of the tab portion I9 of the pintle and the longitudinal edges 39, 40 of the hook portion 20. The edges 37, 38, 39 and 410 are edges formed originally as the inner edges of slots 11, I2 and are consequently in planes parallel to and spacedly inwardly of the edges 35, 36. The edges 37, 38 and 39, 40 are joined with the respective edges 35, 36 by rounded junctures 1316 which are the ends of the original slots l1, l2.

Iclaim:

1. A continuous chain composed of a plurality of interconnected links with each link being composed of a pair of flat parallel longitudinal sides with inner and outer longitudinal edges and integral interjoining transverse pintle and hook ends with each of the pintle ends being composed in part of a portion integral with the sides and extending between the outer edges of the sides and a tab portion bent over the aforesaid portion with the tab portion having outer longitudinal edges spaced transversely inwardly of the respective inner edges of the sides, and each of the book ends being composed in part of a portion integral with the sides and extending between the outer edges of the sides and a cylindrical shaped portion having outer edges spaced inwardly of the inner edges of the flat sides and bent about the pintle end of an adjacent link.

2. The structure as set forth in claim 1 in which the outer edges of the tab and cylindrical shaped portions are substantially coplanar and are in planes parallel to and spaced inwardly of the inner edges of the sides.

3. The structure as set forth in claim 2 in which the outer edges of the tab and cylindrical-shaped portions and the inner edges of the sides are joined at semicircular rounded junctures with said edges extending tangentially from outer sides of the semicircular rounded junctures and the outer edges of the tab and cylindrical-shaped portions extending tangentially from inner sides of the semicircular rounded junctures.

A chain link composed of a pair of flat parallel longitudinal sides with inner and outer longitudinal edges; an integral transverse pintle end composed in part of a portion integral with the sides and extending between the outer edges of the sides, the pintle end further having a tab portion having outer longitudinal edges spaced transversely inwardly of the respective inner edges of the sides; a hook end at the opposite transverse spacings between the outer edges of the pintle end tab portions and cylindrical-shaped tab portions and the respective inner edges of the sides so as to provide smooth uninterrupted junctures therebetween. 

1. A continuous chain composed of a plurality of interconnected links with each link being composed of a pair of flat parallel longitudinal sides with inner and outer longitudinal edges and integral interjoining transverse pintle and hook ends with each of the pintle ends being composed in part of a portion integral with the sides and extending between the outer edges of the sides and a tab portion bent over the aforesaid portion with the tab portion having outer longitudinal edges spaced transversely inwardly of the respective inner edges of the sides, and each of the hook ends being composed in part of a portion integral witH the sides and extending between the outer edges of the sides and a cylindrical shaped portion having outer edges spaced inwardly of the inner edges of the flat sides and bent about the pintle end of an adjacent link.
 2. The structure as set forth in claim 1 in which the outer edges of the tab and cylindrical shaped portions are substantially coplanar and are in planes parallel to and spaced inwardly of the inner edges of the sides.
 3. The structure as set forth in claim 2 in which the outer edges of the tab and cylindrical-shaped portions and the inner edges of the sides are joined at semicircular rounded junctures with said edges extending tangentially from outer sides of the semicircular rounded junctures and the outer edges of the tab and cylindrical-shaped portions extending tangentially from inner sides of the semicircular rounded junctures.
 4. A chain link composed of a pair of flat parallel longitudinal sides with inner and outer longitudinal edges; an integral transverse pintle end composed in part of a portion integral with the sides and extending between the outer edges of the sides, the pintle end further having a tab portion having outer longitudinal edges spaced transversely inwardly of the respective inner edges of the sides; a hook end at the opposite end of the link composed in part of a portion integral with and extending between the sides, and in part of a cylindrical-shaped tab portion having outer edges spacedly inwardly of the inner edges of the sides adapted to overlie the pintle end of an adjacent link; and arcuate junctures extending across the transverse spacings between the outer edges of the pintle end tab portions and cylindrical-shaped tab portions and the respective inner edges of the sides so as to provide smooth uninterrupted junctures therebetween. 